THIS IS A BREAKING NEWS UPDATE. Check back soon for further information. AP's earlier story is below.

Israel's defense minister said that his country won't let recent "rumors and speculation" harm the Israeli-Egyptian peace treaty, an apparent attempt to downplay reports that an Israeli drone killed four militants in a cross-border strike into Egypt.

The late Saturday statement by Moshe Yaalon did not explicitly deny that Israel carried out the Friday attack.

The Israeli military said Friday it was looking into the report. On Sunday it said it had no further comment.

Egyptian officials initially said an Israeli drone carried out the attack, but an official quoted by the state media later claimed an Egyptian helicopter was responsible.

Yaalon said that Israel "appreciated" unspecified actions taken by Egypt against militants over the weekend.

"Israel respects the full sovereignty of Egypt," Yaalon said. He said Israel is "aware of the Egyptian military's increased activity against terror infrastructures in the Sinai Peninsula" and praised the Egyptian military for "fighting first and foremost to protect Egypt's citizens and sovereignty."

A little known militant group, Ansar Jerusalem, said its men were the target of Friday's drone strike into Egyptian territory. It said four militants were killed as they were preparing to fire rockets into Israel.

The Israeli praise of Egypt protecting its citizens seemed intended to deflect reports that Israel carried out a rare cross-border attack to protect its own citizens. Egypt is highly sensitive to criticism about letting Israel carry out strikes on its soil.

The attack could indicate increased cooperation between Egypt and Israel against militants in northern Sinai after a coup ousted Islamist President Mohammed Morsi last month. It also is likely to increase tensions in a border region that has seen other rocket attacks in the past.